<!-- 打印插件在npm run dev模式下 ie下不行，但是当集成到我们布局器后，在ie下可以正常使用 所以如果您使用我们布局器 ，那完全不影响

  如果出现 打印很跟实际情况不匹配 那是因为选中 a4 而界面宽超过a4的宽,浏览器默认缩放成a4纸宽，自然就压缩了
  这个时候调整页面宽即可 a4纸的宽是210mm
  print-id:要打印的区域id属性
  pring-ref:要打印的区域ref属性
  canvas:是否打印canvas "true"|"false"
-->
<template>
  <el-button v-bind="$attrs" @click="printArea" class="no-print">{{text}}</el-button>
</template>

<script>
/*尊重作者 尊重原创，以下打印核心功能来自：github.com/xyl66/vuePlugs_printjs*/
var Print = function (dom, options) {
  if (!(this instanceof Print)) return new Print(dom, options);

  this.options = this.extend({
    'noPrint': '.no-print'
  }, options);

  if ((typeof dom) === "string") {
    this.dom = document.querySelector(dom);
  } else {
    this.isDOM(dom)
    this.dom = this.isDOM(dom) ? dom : dom.$el;
  }

  this.init();
};
Print.prototype = {
  init: function () {
    var content = this.getStyle() + this.getHtml();
    this.writeIframe(content);
  },
  extend: function (obj, obj2) {
    for (var k in obj2) {
      obj[k] = obj2[k];
    }
    return obj;
  },

  getStyle: function () {
    var str = "",
      styles = document.querySelectorAll('style,link');
    for (var i = 0; i < styles.length; i++) {
      str += styles[i].outerHTML;
    }
    str += "<style>" + (this.options.noPrint ? this.options.noPrint : '.no-print') + "{display:none;}</style>";

    return str;
  },

  getHtml: function () {
    var inputs = document.querySelectorAll('input');
    var textareas = document.querySelectorAll('textarea');
    var selects = document.querySelectorAll('select');

    for (var k = 0; k < inputs.length; k++) {
      if (inputs[k].type == "checkbox" || inputs[k].type == "radio") {
        if (inputs[k].checked == true) {
          inputs[k].setAttribute('checked', "checked")
        } else {
          inputs[k].removeAttribute('checked')
        }
      } else if (inputs[k].type == "text") {
        inputs[k].setAttribute('value', inputs[k].value)
      } else {
        inputs[k].setAttribute('value', inputs[k].value)
      }
    }

    for (var k2 = 0; k2 < textareas.length; k2++) {
      if (textareas[k2].type == 'textarea') {
        textareas[k2].innerHTML = textareas[k2].value
      }
    }

    for (var k3 = 0; k3 < selects.length; k3++) {
      if (selects[k3].type == 'select-one') {
        var child = selects[k3].children;
        for (var i in child) {
          if (child[i].tagName == 'OPTION') {
            if (child[i].selected == true) {
              child[i].setAttribute('selected', "selected")
            } else {
              child[i].removeAttribute('selected')
            }
          }
        }
      }
    }
    // 包裹要打印的元素
    // fix: https://github.com/xyl66/vuePlugs_printjs/issues/36
    let outerHTML = this.wrapperRefDom(this.dom).outerHTML
    return outerHTML;
  },
  // 向父级元素循环，包裹当前需要打印的元素
  // 防止根级别开头的 css 选择器不生效
  wrapperRefDom: function (refDom) {
    let prevDom = null
    let currDom = refDom
    // 判断当前元素是否在 body 中，不在文档中则直接返回该节点
    if (!this.isInBody(currDom)) return currDom

    while (currDom) {
      if (prevDom) {
        let element = currDom.cloneNode(false)
        element.appendChild(prevDom)
        prevDom = element
      } else {
        prevDom = currDom.cloneNode(true)
      }

      currDom = currDom.parentElement
    }

    return prevDom
  },

  writeIframe: function (content) {
    var w, doc, iframe = document.createElement('iframe'),
      f = document.body.appendChild(iframe);
    iframe.id = "myIframe";
    //iframe.style = "position:absolute;width:0;height:0;top:-10px;left:-10px;";
    iframe.setAttribute('style', 'position:absolute;width:0;height:0;top:-10px;left:-10px;');
    w = f.contentWindow || f.contentDocument;
    doc = f.contentDocument || f.contentWindow.document;
    doc.open();
    doc.write(content);
    doc.close();
    var _this = this
    iframe.onload = function(){
      _this.toPrint(w);
      setTimeout(function () {
        document.body.removeChild(iframe)
      }, 100)
    }
  },

  toPrint: function (frameWindow) {
    try {
      setTimeout(function () {
        frameWindow.focus();
        try {
          if (!frameWindow.document.execCommand('print', false, null)) {
            frameWindow.print();
          }
        } catch (e) {
          frameWindow.print();
        }
        frameWindow.close();
      }, 10);
    } catch (err) {
      console.log('err', err);
    }
  },
  // 检查一个元素是否是 body 元素的后代元素且非 body 元素本身
  isInBody: function (node) {
    return (node === document.body) ? false : document.body.contains(node);
  },
  isDOM: (typeof HTMLElement === 'object') ?
    function (obj) {
      return obj instanceof HTMLElement;
    } :
    function (obj) {
      return obj && typeof obj === 'object' && obj.nodeType === 1 && typeof obj.nodeName === 'string';
    }
};
export default {
  name:"mc-print",
  props:['printId','printRef','canvas'],
  data:function(){
    return {
      text:this.$slots.default[0].text
    }
  },
  methods: {
    //定义一个工具方法 往结构后面插入新结构
    insertAfter:function(newElement, targentElement) {
      var parent = targentElement.parentNode;
      if (parent.lastChild == targentElement) {
        parent.appendChild(newElement);
      } else {
        parent.insertBefore(newElement, targentElement.nextSibling)
      }
    },
    //根据样式获取结构 兼容老版本浏览器的
    getElembyClass:function(className){
      if(document.getElementsByClassName){ //if it is Firefox
        return document.getElementsByClassName(className);
      }else{
        var tags = document.getElementsByTagName("*");
        var tagsLength = tags.length;
        var result = [];
        for(var i=0;i<tagsLength;i++){
          if(tags[i].className==className){
            result.push(tags[i]);
          }
        }
        return result;
      }
    },
    printArea:function(){
      //处理canvas
      if(this.canvas==='true'){
        //获取界面所有canvas 把他们转成图片 打印canvas的唯一方式
        var canvasList = document.getElementsByTagName("canvas");
        for(var i=0;i<canvasList.length;i++){
          var canvasDom = canvasList[i];
          var style = canvasDom.getAttribute("style");
          var originDisplay = canvasDom.style.display;
          if(typeof originDisplay !=='undefined' && originDisplay!=null &&originDisplay!==''){
            canvasDom.setAttribute("mc-tmp-canvas-display",originDisplay);
          }
          //隐藏canvas
          canvasDom.style.display="none";
          //创建一个图片
          var image = new Image();
          image.src = canvasDom.toDataURL("image/png",1.0);
          image.setAttribute("style",style);//样式也带着过来
          image.setAttribute("class","mc-print-canvas-img-tmp")
          //追加到canvas后面
          this.insertAfter(image,canvasDom);
        }
      }
      //根据print-ref 获取print-id来打印
      if(this.printRef){
        new Print(this.$parent.$refs[this.printRef]);
      }else{
        new Print(document.getElementById(this.printId));
      }
      //还原canvas 把图片删除 原先canvas显示出来
      if(this.canvas==='true'){
        var canvasList = document.getElementsByTagName("canvas");
        for(var i=0;i<canvasList.length;i++){
          var canvasDom = canvasList[i];
          var originDisplay = canvasDom.getAttribute("mc-tmp-canvas-display");
          if(originDisplay==null){
            canvasDom.style.display = "";
          }else{
            canvasDom.style.display = originDisplay;
          }
        }
        //删除image
        var imgList = this.getElembyClass("mc-print-canvas-img-tmp");
        for(var i=0;i<imgList.length;i++){
          imgList[i].remove();
        }
      }
    }
  }
}
</script>
